Toolholder



July 10, 1951 H. G. NORLANDER TOOL HOLDER Filed Feb. 4, 1948 w W 5 M Arron/v5 r- Patented July 10, 1951 UNITED STATES ATENT OFFICE Application February 4, 1948, Serial N 0. 6,162 In Sweden November 14, 1947 2 Claims.

The present invention relates to a tool holder and is characterized by the fact that one end of one or more coil springs is attached to the tool holder body, whereas the other end of said spring or springs is connected to a part turnable in relation to the tool holder body, the coil spring being so arranged that in turning a tool provided with a cylindrical shank, for instance a drill, cutter or the like, in its working direction, said spring is tightened around and securely clamps this tool by the friction between the spring and the tool shank, while turning the spring in the opposite direction causes the turnable part of the spring to be enlarged, permitting the tool to be removed or inserted.

By the present invention it is possible to provide a chuck-like tool holder having a considerably smaller diameter in relation to the tool than has hitherto been possible, but nevertheless clamping the tool securely and at the same time allowing a rapid and simple exchange of tools. This is of great importance especially for multiple spindle drilling machines in which it allows holes to be drilled at a short distance from one another.

The invention will be further described in the following with reference to the construction illustrated in the accompanying drawing.

Fig. 1 illustrates a side view, partly in longitudinal section, of a construction of a tool holder with inserted drill in accordance with the present invention.

Figs. 2 and 3 are transversal sections on the lines IIII and III-III respectively of Fig. 1, while Fig. 4 is a section through the sleeve on the line IVIV in Fig. 3.

Figs. 5 and 6 illustrate the spring in side View and plane view respectively.

In the drawing l designates the tool holder body, the upper part of which is provided, in a manner known per so, with a conical shank 2 or some other suitable means for attaching the tool holder to a drilling machine or the like. The lower end of the body I having an axial bore for the tool that is to be fixed, is provided with a transversal groove 9 in which one end of a coil spring 3 is held fast. In order to further secure the end of said spring its outer portion 6 is bent and inserted into a hole in the bottom of the groove 9. As shown in the drawing, the axial bore for the drill may also be enlarged in such a manner that the coil spring 3 may partly project into the tool holder body I, and thus be guided in a satisfactoryway. The other, likewise 'bent end i of the spring 3 is inserted in a vertical groove 8 in a sleeve 4 turnably journalled on the lower end of the body i, said sleeve being attached to the tool holder body in axial direction by a radially inserted screw (not shown) that projects into a groove I0 in the circumference of the tool holder body. Of course, other locking means, for instance grooves and locking springs,

may also be used for attaching this sleeve. When inserting for instance a drill 5 the sleeve is turned in a direction opening the spring 3 and is released again when the drill has been inserted, thus causing the spring to be clamped around the drill shank, the spring 3 being so wound that, when the drill during the drilling operation tends to rotate backwards in relation to the tool holder body, the spring will be torsion-ally tightened by the friction against the drill shank and clamped around the drill, the tighter the more resistance the drill is exposed to.

The invention is not limited to the construction shown and described above, but may be varied in several ways within the scope of the invention. Thus, for instance, there may also be used two or more springs causing the clamping of the drill to be further improved.

Having now particularly described the nature of my invention and the manner of its operation What I claim is:

l. A chuck for rotatable machinery tools comprising a body member having in the face of one end a cylindrical axial bore and a transverse groove, in a substantially cup-shaped socket member rotatably secured to the body member, the open end of the socket member receiving the said end of the body member, the bottom of the socket member having an opening therethroughin alignment with the bore of the body member for insertion of the shank of a tool to be held, the inner wall of the socket member including an'axial groove, and a helical spring having convolutions of substantially uniform diameter disposed within said socket member, one end of said spring engaging said transverse groove and the other end said axial groove, the inner diameter of the spring convolutions corresponding approximately to the diameter of the shank of a tool to be held in the chuck.

2. A chuck as described in claim 1, wherein the forward end of the body member having said bore and groove in its face is set off relative to the main portion of the body member to form a shoulder engageable with the forward end of the socket member when the latter is secured to the body member, thereby forming a flush connection between the said two members.

HELGE GGSTA NORLANDER.

REFERENCES CITED The following references are of record in the 5 file of this patent:

UNITED STATES PATENTS 2,467,603 Young Apr. 19, 1949 

